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  <div id="layout-content"><div id="function.pcntl-async-signals" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">pcntl_async_signals</h1>
  <p class="verinfo">(PHP 7 &gt;= 7.1.0, PHP 8)</p><p class="refpurpose"><span class="refname">pcntl_async_signals</span> &mdash; <span class="dc-title">Enable/disable asynchronous signal handling or return the old setting</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.pcntl-async-signals-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>pcntl_async_signals</strong></span>(<span class="methodparam"><span class="type">?</span><span class="type"><span class="type">bool</span><span class="type"></span></span> <code class="parameter">$enable</code><span class="initializer"> = <strong><code>null</code></strong></span></span>): <span class="type">bool</span></div>

  <p class="para rdfs-comment">
   If the <code class="parameter">enable</code> parameter is <strong><code>null</code></strong>,
   <span class="function"><strong>pcntl_async_signals()</strong></span> returns whether asynchronous signal
   handling is enabled. Otherwise, asynchronous signal handling is enabled or
   disabled.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.pcntl-async-signals-parameters">
  <h3 class="title">参数</h3>
  <dl>
   
    <dt>
<code class="parameter">enable</code></dt>

    <dd>

     <p class="para">
      Whether asynchronous signal handling should be enabled.
     </p>
    </dd>

   
  </dl>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.pcntl-async-signals-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   When used as getter (<code class="parameter">enable</code> parameter is <strong><code>null</code></strong>) it returns
   whether asynchronous signal handling is enabled. When used as setter (<code class="parameter">enable</code>
   parameter is not <strong><code>null</code></strong>), it returns whether asynchronous signal
   handling was enabled <em class="emphasis">before</em> the function call.
  </p>
 </div>


 <div class="refsect1 changelog" id="refsect1-function.pcntl-async-signals-changelog">
  <h3 class="title">更新日志</h3>
  <table class="doctable informaltable">
   
    <thead>
     <tr>
      <th>版本</th>
      <th>说明</th>
     </tr>

    </thead>

    <tbody class="tbody">
     <tr>
      <td>8.0.0</td>
      <td>
       <code class="parameter">enable</code> is nullable now.
      </td>
     </tr>

    </tbody>
   
  </table>

 </div>


 <div class="refsect1 seealso" id="refsect1-function.pcntl-async-signals-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member"><a href="control-structures.declare.html" class="link">declare</a></li>
  </ul>
 </div>


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